html, body {
  position: relative;
  font-size: 100px;
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
}

body {
  font-size: 0.12rem;
  color: #333333;
  overflow: hidden;
  box-sizing: border-box;
}

header {
  position: relative;
  height: 0.44rem;
  line-height: 0.44rem;
  color: white;
  text-align: center;
  font-size: 0.15rem;
  background-color: #29b482;
}

header .nav-back {
  position: absolute;
  left: 0;
  top: 0;
  display: inline-block;
  width: 0.54rem;
  height: 100%;
  background-image: url();
  background-repeat: no-repeat;
  background-position: center;
  background-size: 0.2rem auto;
}

h1 {
  text-align: center;
  padding: 0.2rem;
}

.btn {
  height: 0.4rem;
  line-height: 0.4rem;
  text-align: center;
  color: white;
  background: #29b482;
  margin: 0.12rem;
}